qr

README

qr

qr is a library for generating QR Codes in pure Go.

go get github.com/AlexEidt/qr

Usage

qrcode, err := qr.NewQRCode("QR Code", &qr.Options{Error: "H"})
if err != nil {
    panic(err)
}

qrcode.Render("qr.png", 10)

Below are the functions available for a QRCode.

qr.NewQRCode(data string, options *qr.Options) (*qr.QRCode, error)

Version() int
Mode() int // 1: numeric, 2: alphanumeric, 4: byte
ErrorLevel() string // L, M, Q, H
Bitmap() *qr.Bitmap
Render(filename string, scale int) error // .png, .jpg, .svg supported

Options

When building a QR Code, certain parameters can be specified such as the Version, Mode and Error Correction Level.

type Options struct {
	Version int
	Mode    int
	Error   string
}

Parameter	Description
Version	The version of the QR Code to be generated. Must be between 1 and 40. Defaults to lowest version that fits the given data.
Mode	The mode of the QR Code to be generated. Must be qr.Numeric, qr.AlphaNum, or qr.Byte. The best fit is found based on the given data. See the Supported Modes section below for the characters that can be used in each mode.
Error	The error correction level of the QR Code to be generated. Must be L, M, Q, or H. Defaults to L. Level L can correct ~7% of errors, M can correct ~15% of errors, Q can correct ~25% of errors, and H can correct ~30% of errors.

Supported Modes

Currently, only Numeric, Alphanumeric and Binary modes are supported for data encoding.

Mode	Character Set
Numeric	0123456789
Alphanumeric	0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:
Binary	ISO/IEC 8859-1

Notes

• Kanji mode is not supported.
• Structured Append mode is not supported.
• Extended Channel Interpretations (ECI) mode is not supported.
• Model 1 QR Codes are not supported.

Acknowledgements

The following resources were helpful in building this library:

• The pyqrcode repository by mnooner256: https://github.com/mnooner256/pyqrcode
• The QR Code Tutorial at: http://www.thonky.com/qr-code-tutorial/
• The QR Code Tutorial at: https://www.matchadesign.com/news/blog/qr-code-demystified-part-1/

Documentation

Index

• Constants
• type Bitmap
  • func NewBitmap(width, height int) *Bitmap
  • func (b *Bitmap) At(x, y int) bool
  • func (b *Bitmap) Copy() *Bitmap
  • func (b *Bitmap) Fill(x, y, w, h int, value bool)
  • func (b *Bitmap) Height() int
  • func (b *Bitmap) Invert()
  • func (b *Bitmap) Place(x, y int, other *Bitmap)
  • func (b *Bitmap) Set(x, y int, value bool)
  • func (b *Bitmap) Width() int
• type Buffer
  • func NewBuffer() *Buffer
  • func (b *Buffer) Add(val, size int)
  • func (b *Buffer) Bytes() []byte
  • func (b *Buffer) Clear()
  • func (b *Buffer) Size() int
  • func (b *Buffer) String() string
  • func (b *Buffer) Write(data string)
• type Options
• type QRCode
  • func NewQRCode(data string, options *Options) (*QRCode, error)
  • func (qr *QRCode) Bitmap() *Bitmap
  • func (qr *QRCode) ErrorLevel() string
  • func (qr *QRCode) Mode() int
  • func (qr *QRCode) Render(filename string, scale int) error
  • func (qr *QRCode) Version() int

Constants

const (
	Numeric  = 1
	AlphaNum = 2
	Byte     = 4
)

Types

type Bitmap

type Bitmap struct {
	// contains filtered or unexported fields
}

func NewBitmap

func NewBitmap(width, height int) *Bitmap

func (*Bitmap) At

func (b *Bitmap) At(x, y int) bool

func (*Bitmap) Copy

func (b *Bitmap) Copy() *Bitmap

func (*Bitmap) Fill

func (b *Bitmap) Fill(x, y, w, h int, value bool)

func (*Bitmap) Height

func (b *Bitmap) Height() int

func (*Bitmap) Invert

func (b *Bitmap) Invert()

func (*Bitmap) Place

func (b *Bitmap) Place(x, y int, other *Bitmap)

func (*Bitmap) Set

func (b *Bitmap) Set(x, y int, value bool)

func (*Bitmap) Width

func (b *Bitmap) Width() int

type Buffer

type Buffer struct {
	// contains filtered or unexported fields
}

func NewBuffer

func NewBuffer() *Buffer

func (*Buffer) Add

func (b *Buffer) Add(val, size int)

func (*Buffer) Bytes

func (b *Buffer) Bytes() []byte

func (*Buffer) Clear

func (b *Buffer) Clear()

func (*Buffer) Size

func (b *Buffer) Size() int

func (*Buffer) String

func (b *Buffer) String() string

func (*Buffer) Write

func (b *Buffer) Write(data string)

type Options

type Options struct {
	Version int
	Mode    int
	Error   string
}

type QRCode

type QRCode struct {
	// contains filtered or unexported fields
}

func NewQRCode

func NewQRCode(data string, options *Options) (*QRCode, error)

func (*QRCode) Bitmap

func (qr *QRCode) Bitmap() *Bitmap

func (*QRCode) ErrorLevel

func (qr *QRCode) ErrorLevel() string

func (*QRCode) Mode

func (qr *QRCode) Mode() int

func (*QRCode) Render

func (qr *QRCode) Render(filename string, scale int) error

func (*QRCode) Version

func (qr *QRCode) Version() int